1. Field of the Invention
This invention relates to systems for safeguarding the persons of bed occupants and in particular to a system for detecting high temperature conditions in a bed and the absence of the occupant thereof and for signalling such unwanted conditions.
2. Prior Art
Systems are known which protect bed occupants by detecting their undesired absence from their beds and producing a signal to alert supervisory personnel. Some of these systems have electrical switches connected to the side rails on the bed which detect when the occupant tries to climb over them. There is some danger to the patient from the electricity present at the switches and from pinching of the patients' fingers. This system is also unable to detect exit from the bed by way of the headboard or footboard.
Other systems (U.S. Pat. No. 3,781,843) have used fluid-filled sensors attached to the tops of the headboard, footboard and side-rails. The pressure in the sensors increases when grasped by the patient as he attempts to get out. With such systems there is always the problem of fluid leaks and the problem of adapting the sensors for securement to the different structural characteristics of different types of beds.
Still other systems use single-function mats of the fluid-pressure-sensing (U.S. Pat. No. 3,727,606) or electrical characteristic types (U.S. Pat. No. 2,818,477; 3,760,794; 3,926,177) either to monitor the patient's life signs or detect bed absence. They produce a signal corresponding to the function. No system is known which can, in a single compact sensing mat, detect two different perils and generate two different alarm signals.
It is therefore among the objects of the present invention to provide a dual-purpose bed security system for detection and signalling two different perils to the bed occupant.
Another object is to provide a dual-purpose system which can be associated with any bed of any construction.
Still another object is to provide a dual-purpose system which can be patched into an existing nurse call system and provide two different additional alarm signals distinguishable from the customary signal generated by the patient himself.
Other objects of the invention will occur to those skilled in the art upon perusing the following specification and claims in conjunction with the drawings herein.